Tag Archives: decimal comparison

If you’re outside (or wish you were!) here’s another math game worth playing. It’s called Testing the Limits — and I’ve adapted it from BEAM Maths of the Month.

This version is adaptable for all grade levels and can be played outside with sidewalk chalk (or indoors on paper!).

To play, you need sidewalk chalk and a die (6-sided is fine, 10-sided is better!). You can play this game with a partner or alone. Here’s how…

ROUND 1: Roll the die 3 times and make a 3-digit number. Roll 3 more times and make a second 3 digit number. Put both numbers on the same number line. These are your “limits”.

ROUND 2: Now roll 6 more times. Make 2 different 3-digit numbers that fit within the limits from ROUND 1. Plot them on the same number line as ROUND 1. If you can do it, these new numbers become your new limits and you can move onto ROUND 3. If not… the game is over! Check out my sample game below.

Try using just two 2-digit numbers for younger students, or even decimal numbers for older students. Consider trying this with negative numbers, or even one negative and one positive to explore both sides of zero.

I wanted to share something I put together not long ago to support students in understanding the value of the digits when we write decimal numbers. These decimal “tents” as I call them, are made from card stock and are folded in half to form a tent shape. Each one is cut so that the decimals on each card line up one under the other – but the digits themselves are still visible. It’s a bit hard to explain, I fear, but the following pictures should help…

This is what the cards look like, folded. I like to put a strip of magnetic tape on the back of each one so that I can stick them on the board, matching them to a model to show the same amount.

The cards are trimmed so that the decimal point falls at the same location on each of the “expanded” decimal number. On the decimal tents line master, this means you’ll slice off the light grey zeroes…

So when the cards are overlapped, the decimal number itself is clear, and made up of the parts.

It’s a powerful tool to use with students. Helping them to see that we can decompose a decimal number in the same way we do whole numbers is an important connection! This decimal tent set shows that 3 + 0.6 + 0.08 = 3.68.

Imagine a series of these tents strung along a string or wire in your classroom. Have students create a 3 digit decimal number, model it with materials and then order that number along the number line (that is, to hang their cards right on the wire!) placing it relative to the others. It’s a neat way to compare and order decimal numbers!

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Welcome!

I am Carole Fullerton, an independent consultant working with teachers around British Columbia (and beyond!) in the area of numeracy. I work with districts, whole school staffs, with school-based learning teams, in classrooms and with parents in an effort to promote mathematical thinking.